Process of producing a shrinkable cellulose textile filament

ABSTRACT

In the manufacture of regenerated cellulose fibres having a high shrinkage potential, e.g. 20-30% when immersed in boiling water with elongation at break of about 20% (wet), viscose is spun at a speed of 70-120 metres per minute through a tube immersed in a spinning bath and coaxial with the spinneret, the acidity of the bath being 120-125 grms. of sulphuric acid per litre, sodium and zinc sulphate contents 230-250 and 125-130 grms. per litre, the salt point being above 7% and the viscose being heated to the temperature of the bath immediately on the upstream side of the spinneret, and the filaments are dried under a tension sufficient to prevent shrinkage.  These filaments (then having elongation at break of about 45%) are wet stretched, e.g. in a dilute aqueous bath at 85 DEG  C., in one or more stages to a degree close to their elongation at break, e.g. 60-70% thereof or 30% of their original length, before or after the drying operation.  On leaving the spinneret, the filaments are drawn up to 25%.  The viscose or the bath may contain one or more components e.g. thiodiglycol and polyhydroxyethylenes, which promote formation of thick-skinned filaments.  The filaments may be stapled by cutting or stretching to break, e.g. by the process described in Specification 774,360, [Group IX], and the filaments or staple fibre may be blended with filaments or fibres having high tenacity, low elongation and high resistance to shrinking under the action of hot water, e.g. cellulose acetate fibres or viscose fibres obtained by the process described in Specification 650,896, and spun into yarn. Bundles of the two forms of filaments may be formed into a blended yarn which is drafted to break the filaments into staple lengths within the yarn.  The composite yarn is bulked by subsequent subjection of yarn or fabric made therefrom to the shrinking action (on one yarn constituent) of a hot aqueous medium which may be combined with dyeing and followed by treatment with 5% of a ureaformaldehyde resin to render the fabric crease-and shrink-proof to washing.  Specifications 655,516 and 778,746 also are referred to.

PRQCESS OF PRODUCING A SHRINKABLE CELLULOSE TEXTIIJE Nicnlas Drisch and Piene Schneller, Pars, France, as-

signors to Chimiotex Societe Anonyme, 'Iangner, North Africa, a corporation of Tangier Filed Dec. 14, 1956, Ser. No. 628,217

Claims priority, applcation France Dec. 14, 1955 1 Claim. (Cl. 18-54) This invention relates to a method for produeinghigh bulk yarns composed of a mixture of sbrinkable -and non-sbrinkable fibers, and has for an object to provide novel and improved methods for producing fibers for use in such yarns.

Accordin g to the present invention, new bigh-bulk yarns =are obtained by a treatment in a. very hot -aqueous medium without tension, of yarns containing on the one band shrink-proof fibers and on the other artificial cellulosic fibers having high shrinkage under these conditions.

More specifically, these yarns are obtained by asso ciation of a sliver of shrink-proof filaments and of a continuous sliver of shrinkable artificial cellulose filaments with high elongation.

The continuous shrink-proof fila-ments may be cellulosic filaments having very high tenacity and low elongation, which are obtained by the process described in French Patent No. 985,847 (U.S. Patent No. 2,586,796). Continuous filaments having very high elongation, which are more particularly suitable for use in the new yarns according to the invention, may be obtained by the viscose process With the -application of various measures, in any desired combination.

(a) Spinning is carried out at low speeds, for example from 15 meters to 30 meters per minute. This speed may, however, be increased up to from 70 meters to 120 meters per minute by employing a tube aligned With the spinneret described in French Patent No. 1,006,078, dated November 1947 (U.S. Patent No. 2,511,699, dateci June 13, 1950).

(b) Spinning in a single coagulating bath, containing about 115 grams per liter of sulphuric acid; 250 grams per liter of sodium sulphate; and 120 grams per liter of zinc sulphate. At the higher spinning speeds the acidity should be slightly increased, for example to 120 grams to 125 grams per 1iter of sulphuric acid and the zinc sulphate should be increased for exarnple -to 125 grams to 130 grams per liter. A viscose having a high sodium chloride salt point of more than 14 and preferably more than 16, as determined in accordance With the procedure set forth in the Brandenberger Patent No. 1,544,631, should be used.

(c) Reduced drawing at spinning, just sufficien-t to produce ari appropriately organized and oriented filament (10% to 25%). This drawing should not exceed about 20%, While the filaments preferably subseqnently undergo, in a second dilute bath at 85 C. at least, a bigh drawing of at least 30%.

(d) Addition to the viscose and/or -to the bath of agents giving rise to the formation of thick-skinned filaments, such as amines or polyglycol ethers.

(e) The final drawing, after Wet finishing, or even after dry finishing of the purified filament, can reaoh 60% of the elongation at break. Wet drawing is carried out in all cases, and it is essential to dry under tension without any possibility of sbrinkage.

The most important conditions ore (a), (c) and (e), and it has been possibie to obtain, for example, With a t. States Pate fl 0 2,954,270 Patented Sept. 27, 1960 normal viscose spun at 25 meters per minute, with 20% (French) which is wound 011 cops.

drawing during spinning, a yarn having an elongation of 45%, whioh may be 20% in the Wet state, and which is thereafter dried under tension to -give a yarn which shrinks by 20% to 25% in e. boiling water bath.

The drawing is a flow sheet illustrating the preferred embodirnent of the invention.

The invention Will be better understood by referring to the examples and the c1aims attahed hereto.

Example 1 A sliver of 3300 denier/ 1440 filaments having very high elongation as in the foregoing is doubled with a sliver of 3300 denier/ 8000 filaments of regenerated cellulose having a dry tenacity of 6.8 grams with an elongation of 9.5%, and the double sliver is subjected to drawing to breai ing point on the device described in U.S. Patent No. 2,746,091, for a device for the mannfiacture ocf mixed yarns, whereafter the bro ken yam is drawn and twisted in such manner 'as to form a No. yarn This yarn has a sbrinkage of 25% in boiling water and thus acquir-es high bulk.

Example 2 There are prepared yarns having a rnoist elongation viscose, containing 2% of thiodiglycol (according to French Patent No. 1,111,580, dated September 3, 1954; U.S. Serial No. 532,799, filed September 6, 1955, now Patent No. 2,912,299) With a drawing at spinning of 20%. This sliver is then drawn by 18% and dried under tension. The shrinkage on wetting of the fiber obtained is then 23%.

This fiber out to millimeters is mixed in a proportion of 50% With a fiber spun under similar conditions, the drawing of which during spinning was This fiber has been freely dried and the shrinkage in boiling water was only 1%.

The mixture of the two fibers is worked on conventional equipment for carded wool, and a No. 40 yarn (metric) is forrned With a twist of 400 turns. This yarn is woven in twill weave and this fabric is then dyed With the aid of a mordant. During the dyeing, a shrinkage of 35% occurs in each dirnension. The apparent bulk of the yarn is about twice that of the initial yarn.

The fabric thus obtained only requires a finishing treatment With 5% of unreaformaldehyde. The finished fabric is completely erease-resistant and shrinkproof in washing, and has the characteristics of a. woolen fabric.

Example 3 Seme ex-ample as before, but the shrinkable yarn is mixed With 50% of a normal acetate fiber.

The fabric obtained is crease-proof and shrink-proof Without any further treatment.

Example 4 A viscose containing 9% of cellulose and 6% of oaustic soda, prepared With the -aid of 50% carbon disulpbide, ealcul-ated on the alpha cellulose and containing 0.15 millimol of waxy polyhydroxyethylene to 100 grams of alpha cellulose, is spun at a sa1t point of 16.5 into a bath containing 120 grams of sulphuric acid, 231 grams o=f sodium sulphate and 128 grams of zinc sulphate per liter. The bath is at 48 C. and the viscose is preheated to this temperature immediately on the upstream side of the spinneret.

The spinning device comprising a tube 'as described in French Patent No. 1,066,078 (U.S. Patent No. 2,511,699) referred to above is employed. On leaving the spinning bath, the yarn passes over a first feed roller, which eiects a 12% drawing of the yarn in relation to the speed of the viscose in the spinneret holes. The yarn then passes into a secnd 1% sulphuric acid bath heated 'at 89 0, :and is taken up on- 1eaving this bath by a second feed roller running at a tangential velocity 30% higher than that of the first feed ro11er. It is thenwound at the same or a slightly higher speed onto a rigid bobbin, the linear Winding speed bei-mg of the order of 75 meters per minute.

After Winding to a sufiicient depth of yarn on the bobbin, the wound mass is washed on the bobbin and then desulpnurized With a hot dilute alkaline bath and, if desired, bleached and boiled.

The yarn is then unwound and again -drawn by 18%, whereafter it is wound on another rigid bobbin, on Which it is subjected to drying.

The dried yarn has a tenacity of 3.5 grams in the dry state -and 2.5 grams in the wet state, With an elongation at break of 12% in the dry state and 17% in the wet state. On wetting followed by drying without tension, it is capable of a shrinkage of 30%.

Example A group of 10,000 filaments is spun and continuously treated, whereafter it is passed aver a member permitting of the most complete po-ssible relaxation and is again continuously hot-drawn, the drawing being 70% of the elon-gation at break in the wet state, that is to say, 40% in the exarnple chosen. The group of -filaments is then dried un heated rollers without any possibility of shrinkage.

In both cases, the group of filaments obtained can be out into sections or converted into a tow of discontinuous fibers on a machine of the converter type or by drawing to breaking point on a stapling frame.

It is obvious that the invention is in no way 1imited to the specific examples described, but also inc1udes any modifications in the same spirit. It should be emphaszed that the shrinkage is noi: necessarily produced on the mixed yarns. It is advantageously produced on articles w0ven or knitted With said yarns for the purpose of producing swe11ing efects and a softer handle.

What is c1aimed is:

The process of producing a shrinkable cellulosic textile filament, which comprises spinning into a bath having an -acidity of 125 grams :to 130 grams sulphun'c acid per 1iter and a zinc sulphate content of 125 grams te 130 grams per liter having a temperature of about 48 C. in the presence of a po1yglycol modifying agent Which delays coagulation, viscose having a sodiurn chloride sa1t point greater than 14 and preheated to the temperature of the bath at a. rate of meters to 120 mcters per minute through a confined zone With less than 20% drawing during the spinning, drawing the spunfilarnents in a bath having a temperature of C. to 89 C. to an elongation in excess of 30% washing and finishing drawing s-aid finshed filaments in an additional stage by about 18% and drying under conditions to prevent shrinkage.

References Citefi in the file of this patent UNITED STATES PATENTS 2,369,190 Thurmond Feb. 13, 1945 2,511,699 Drisoh June 13, 1950 2,535,044 Cox Dec. 26, 1950 2,696,423 Dietrich Dec. 7, 1954 2,852,333 Cox Sept. 16, 1958 

